Seeding Your C-Section Baby with Vaginal Fluids

You may have heard of the benefits of exposing a C-section baby to vaginal bacteria, but most doctors don’t recommend the procedure yet.

As they’re pushed out into the world, most babies are coated with secretions from their mother’s vagina. Full of healthy bacteria, it’s thought that these secretions form the basis for a baby’s microbiome — the collection of bacteria that inhabit their body — and help the newborn’s gut and immune system develop.

But the approximately 1 in 3 babies in the U.S. who are born through Cesarean section don’t get this initial first dose of vaginal bacteria (though they're quickly exposed to bacteria from their parents bodies as they snuggle and eat). Recent research has suggested that this may be one reason for higher rates of asthma and allergies in babies born through C-sections, and it’s led some parents to try something new: swabbing their baby with vaginal fluids just after they’re delivered. But the jury’s still out on just how safe — and how beneficial — this practice is.

What is vaginal seeding?

Over roughly the past decade, scientists have discovered that the trillions of bacteria and viruses that live on and in your body — in your gut, nose, skin and genitals — are an important part of keeping you healthy. They’ve also found that all sorts of things, including what you eat and where you live, influence your microbiome.

When it comes to babies, researchers are just starting to understand how a newborn’s microbiome first gets established. In 2013, a study showed that the gut bacteria in newborns delivered through Cesarean section are different from those of babies who were born vaginally. Different isn’t always a bad thing, but some scientists suspect that the lack of some bacteria in the C-section babies’ guts might be one reason that they’re more prone to some immune diseases. If this is true (and researchers don’t know that for a fact yet), then exposing babies born by C-section to vaginal bacteria might help them get a healthier start to life.

How does vaginal seeding work?

Since vaginal seeding is still experimental, there’s no one method that scientists or doctors have settled on to expose babies to vaginal bacteria. In one recent study, doctors put a piece of gauze, folded up into a tampon shape, into a pregnant woman’s vagina 60 minutes before her scheduled C-section. Then, just a minute or two after her baby was delivered, the newborn’s body — including his face and mouth — was swabbed with the gauze.

Are there any benefits to vaginal seeding?

So far, researchers have shown that seeding a C-section baby with vaginal fluids from their mother makes their gut — for the first few months of life at least — more similar to that of a baby born vaginally. But the jury is still out on whether that impacts their long-term health. Researchers hope that vaginal seeding of babies born through C-sections would decrease the babies’ risks of asthma, hay fever, food allergies and perhaps even obesity.

What are the potential risks of vaginal seeding?

As more parents-to-be are learning about vaginal seeding and starting to ask their healthcare practitioners about the procedure, some doctors are cautioning that it may be too early to recommend seeding.

Not only are there no studies that show any long-term benefits of exposing C-section babies to vaginal fluids, but the procedure could expose babies to unwanted bacteria, including herpes, syphilis and group B strep. These infections — even when mild in an adult — can cause severe symptoms and permanent damage to infants. In the studies being done currently, mothers are tested to make sure they don’t have any infections that they could transmit to their baby. If these tests aren’t done, seeding could put C-section babies at unnecessary risk.

Where and when is vaginal seeding done?

Although there’s no set protocol for vaginal seeding yet, researchers agree that it has to happen almost immediately after birth to have any potential impact. So that means in the operating room after a C-section, not hours or days later in a hospital recovery room or at home. Because of the risk of transmitting an infection — and the need to keep any vaginal sample in a clean environment so it’s not contaminated with outside bacteria — it’s important that vaginal seeding is only done by a healthcare practitioner.

If you know you’re having a C-section (or want to prepare for the possibility of having one) and are interested in vaginal seeding, you can bring it up with your doctor. While the procedure is becoming more commonplace, not all doctors are comfortable with carrying it out.

How to give your baby a healthy microbiome

However your baby is born, there are a few things other than vaginal seeding that you can do to make sure their microbiome gets off to a healthy start. Just as babies born vaginally have been shown to have a more diverse and beneficial collection of bacteria in their guts compared to babies born through a C-section, breastfeeding has also been shown to shape the microbiome toward a healthy balance of bacteria. Similarly, avoid giving your baby antibiotics (except when absolutely necessary), which can also help their microbiome develop properly.

From the What to Expect editorial team and Heidi Murkoff, author of What to Expect When You're Expecting. Health information on this site is based on peer-reviewed medical journals and highly respected health organizations and institutions including ACOG (American College of Obstetricians and Gynecologists), CDC (Centers for Disease Control and Prevention) and AAP (American Academy of Pediatrics), as well as the What to Expect books by Heidi Murkoff.

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What to Expect When You're Expecting, 5th edition, Heidi Murkoff and Sharon Mazel.